Zone metering system



Dec. 10, 1929. R. F. sTEHLlK 1,738,931

ZONE METERING SYSTEM original Filed Feb. 12, 192e;u 4 sheets-sheet i;

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ZONE METERING SYSTEM Original Filed Feb.. 12, 1926 4 Sheets-Sheet 4 @MQW fin-gy.-

Patented Dec. I, 19.29

UNITED STATES PATENT" OFFICE RUDOLPH F. STEHLIK, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

" AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, `A CORPORATION OF DELAWARE ZONE METERING SYSTEM Application filed February 12, 1926, Serial No. 87,742. Renewed March 18, 1929.

The present invention relates to zone metering telephone systems in general, but is concerned more particularly with zone metering telephone systems in which calls are extended through the medium of automatic switches; and the principal object, briefly stated, is the provision of new and improved circuit arrangements for such systems in which the calling subscriber is charged for a completed call according to the Zone in which the exchange of the called .subscriber is located, the charge being independent of the number of inter-exchange trunk lines engaged in serial relation andV independent of the route by which the called subscriber is reached, and in which the measured service equipment is located in the exchange in which the calling subscribers line terminates.

Another object is the provision of improved circuit arrangements, whereby the initial charge made at the beginning of the conversation is repeated at definite intervalsy throughout the conversation, to assess an elapsed time charge against the calling subscriber which is proportional to the length of the conversation and the zone in which the called partys line terminates.

In the past, zone metering systems have been developed to assess a charge against the calling subscriber in accordance with the zone in which the called partys line terminates, but in such` systems the charge assessed was dependent directly upon the route taken by the call. While these systemsfunctioned entirely satisfactorily when used in connection with an automatic telephone system of the usual type in which the first digit indicated a district and the second an oliice therein,

each other to determine the zone, they proved inadequate for use in a system in which the oflice designation digits are so chosen that two or more digits are required to determine the zone, those digits bearing no direct relation to each other.

The ela sed time metering systems. have been 4deve oped to assess the charge'against the calling subscriber in accordance with the len h of the conversation and the zone in which the called partys line terminates, but

these two digits being in direct relation to' such systems have been extravagant in the use of moving equipment which is individual to the trunk. This use of individual moving switch mechanisms, causes a high installa` tion and maintenance cost, this high cost seriously impairing the advantages gained by such a system.

Accordingly, a further object of this inv ention'is to provide a Zone and elapsed time metering system in. which all of the constantly moving charge assessing equipment is common to an exchange or to a large group of trunk lines, and in which the equipment individual to anyone of said trunks is reduced to the minimum. In carrying out this object, I have provided a Zone marking switch which is common to a group of trunks and which 'is associated with an idle one of said trunks through the assistance of a distributor. This zone marking switch is associatedwith that trunk only during the idle period and during the time required to set up a connection. When the digits of the called number which determine the charge have been dialled, the zone marking switch releases itself from the connection and is associl ated with another trunk line by the distributor switch.

A further object of this invention is to provide circuits for rendering a trunk inaccessible to a calling line until a zone marking switch is associated withthat trunk, thereby eliminating the possibility of false metering due to a call being started over a trunk line before the common zone marking equipment is in readiness to receive and register the charge marking digits.

In carrying out the foregoing object in this invention, I have provided a series of constantly moving cams through which the elapsed time charges are assessed against the calling line. Associated with and individual to each trunk, I have provided a time metering switch which is actuated by the response of the called a'rty to search and seize a cam set which is just beginning a time interval, thereby insuring thatthe calling subscriber will not be assessed an elapsed time charge il' i,

. ated here, will be apparent from the detailed specification and claims which follow.

The drawings comprising Figs. 1-4, inelusive, are arranged with Figs. 2 and 3 underneath Fig. 1 and Fi 4 to the right of Fig. 1, with the correspo ing lines in ali nment, show suiicient circuit details to ena le a thorough` understanding of my invention.

Referring now to Fig. i1 in more detail, I have shown the calling subscribers station A, which comprises the usual automatic telephonefinstrumentalities, and which is connected to the individual line switch C, by the line conductors 1 and 2. The line switch C may be of the well known rotary type, in whlch the wipers move in a single plane and in one direction only, standing, 'when idle, on the contacts last used. Accessible to the line switchC is the first selector E which may be of the well known Strowger twomotion type in which the shaft carrying Wipers is elevated under control of the calling device until the wipers stand Opposite the desired row or level, and rotated automatically into that level in search of an idle trunk line. Accessible to the selector E is the trunkline comprising conductors 9n11, which terminate.A in the repeater R. The repeater R, which is the well known reverse battery impulse repeater, comprises only relays, through which circuits are completed in accordance with the objects of this invention.

n `the lineswitch C, with circuits modified in In Fig. 2, I show the zone metering relay group ZMR which is yindividual to the repeater R, and through whichv the initial and elapsed time charges are assessed against the calling line. Associated .with the zone meter relay groups are a plurality of zonemarking switches', such as ZM, arranged to associate themselves with the zone metering relays through the medium of wipers 250-253, vinclusive, and under 'the control of distributor D, and its wipers 274 and 277. `A zone marking switch ZM is common to a plurality of trunks, and the distributor switch'D is commlpn to a plurality of zone marking switches Z The distributor switch D and the zone marking connecting switch comprising wipers 250-253 are mechanically the same as accordance with the functions performed. The zone marking switch ZM, is mechanically like a connector, such as H. The wipers 278-279. of ZM move first in a vertical direction under the control of impulses delivered over the conductor 68, coming lto rest at the end ofthe digit op site the bank level corresponding to that igit, and move then in a horizontal direction under the control of impulses delivered over conductor 68. The bank contacts of the marking switch ZM are connected to a cross connecting frame F, through which they are connected to ground jumpers as required.

In Fig. 3, I have shown a time metering switch TMS, which is individual to the zone metering relay group ZMR, and which has access to 'a plurality' of time metering springs, through its wipers and banks. In Fig. 3, I have also shown initial charge and pick-up cams, which co-operate with the zone metering group ZMR to assess the initial charge against the calling subscriber.

In Fig. 4, I have shown the incoming selector E2 in which the trunk line comprising conductors 50 and 51 terminates. Accessible from the banks of this incoming selector, which is identical in every respect with the selector E', is the local selector E through which calls to the subscribers in the exchange in which E2 is located are routed. Accessible from other levels of the selector E2 are trunk lines leading to distant eX- changes, over which calls to subscribers in those exchanges are routed. One of these trunk lines comprising the repeater R2, the trunk, and the incoming selector E, located in the distant office, is shown in schematic form. The selector E, is mechanically and electrically identical with the other selectors shown in this case, and has access to its banks and Wipers to a local switch train and to trunk lines leading to a more distant exchange.

Throughout the drawings I have shown a plurality of batteries, this being done -to simplify the drawings as much as possible. In an installation, there would be but one batteryV in each exchange, preferably with its positive pole grounded.

In order to explain the operation of. my

invention in detail, it will be assumed that the v subscriber at substation desires to call the party whose number is taken to be 25610, and that t hat partys line terminates in the banks 'of the connector switch H shown in Fig. 4.

It is further assumed that the oice containing the switches E", E", and H is an office in the first zone from the oiiice in which the subscribeds line A terminates, and that a unit charge is made for calls to that zone. The

subscriber A, upon removing the receiver from a telephone completes a circuit for the relay 28 of his individual line switch C, causing that relay to energize and prepare a circuit for the motor magnet 29, which operates in the 'well known manner until the wipers 3-5 of the line switch are standing upon the terminals of an idle trunk. The relay 27 then energizes and extends the conductors 1 and 2 of the calling line through the springs 8zand 6, respective y, and the wipers 5 and 3, respectively, to the control relay of the next switch, which in this case is assumed to be the selector E. The switch E', which is not an essential part of this invention, may be any well known selector switch, such as that shown in detail on pa es 62 and 63 of the second edition -of the boo Automatic Telephony by Smith and Campbell. This switch operates in response to the iirst digit of the number dialled by the calling subscriber to elevate its wipers opposite the level containing trunk lines leading to the next switch to be used in the call. In the case of the call now being considered, the calling subscriber will dial 2 for the first digit, transmitting two impulses to the control relay of the switch E which steps its wipers two steps. At the completion of the transmission of this series of impulses, the switch E rotates its wipers automatically in a horizontal direction, searching over the bank contacts to find an idle trunk line, in this case assumed to be the trunk ,line leading to the repeaterR. The operation of the switch E in performing this function being well known and explained in detail in the above reference, need not be re- 2o peated at this time. Whcn the switch E has' positioned itswipers on contacts 9 and 11', inclusive, leading to the repeater R, it performs certain switching functions which extend the conductors of the calling line through the switch E to lthe repeater R, the

extended-conductors being free from all atta'chments. A circuit may then be traced from ground through the lower winding of relay 22, through normally closed contacts controlled by spring 28', over conductor 11, contact 11 and the associated wiper of switch C, through wiper 5 of the switch C, through spring`8 and its make contact, line conductor 1, through the calling telephone to line conductor 2, through spring 6 and its make contact, wiper 3 of the switch C, through the wiper of switch' E associated with the contact'9` through conductor 9. through the normally closed springs controlled by spring 27 of the relay 21, throughthe upper winding of relay 22 to grounded battery. Relay 22 energizes over this circuit and at springs 33 closes the obvious circuit for the relay 23. Re-

lay 23 energizes and at springs 35 closes a circuit from ground on the normally closed springs controlled by springs 235 of the zone metering relay group, conductor 62, spring 35 and its make contact, conductor 10,'through the contact 10 and the wiper of E associated therewith, thence through `wiper 4 ofthe switch C, spring 7 and its make contact, through the winding of relay 27, holding the relay 27 in energized position, and holding a relay of the switch E in energized position, and marking the trunk line 9--11 engaged to other switches whose wi ers have access to it. Relay 23 at springs 36 c oses a circuit for relay 25,`and its spring 34 closes a point in a bridged circuit across 'the conductors 50 and 51. Relay 25, upon energizing, closesa circuit from ground through spring 41 and its makev contact, through the llower winding of polarized relay 24. energizing that winding without eiect at this time. The repeater R hav- 35 ing thus been seized, a circuit maynow be .pose of explaining the call in progress, it will traced from ground through the lower winding of relay 401 of the switch E2, Fig. 4, through the break contact and main spring of the lower spring set controlled by the relay 403, trunk conductor 51, spring 32 and its make contact, through the right hand l winding of impedance coil 31, through the normally closed springs controlled by spring 30, conductor 56, through the upper winding of polarized relay 24, through the spring 43 and its break contact, conductor 58, springs 34, trunk conductor 50, through the break contact and upper spring of relay 403, through the upper winding of relay 401 to grounded battery. v Relay 401 energizes in this circuit, but relay 24 does not energize at this time for the reason that current is flowing through the upper and lower windings in opposite directions. Relay 401, Aupon energizing, closes a circuit for relay 402 which energizes to protect the switch E2 and to prepare the impulsy ing circuit therefor in the manner explained in detail in the above reference.

In the foregoing description of the seizure i of the repeater R, it was assumed the repeater was selectable at the time the call being cle-- scribed was being made. In order that the repeater R may be selected by the switch E. it is also necessary 'thata zone marking switch, such asZM, be associated with the repeater, 9 otherwise, the repeater R is rendered unselect-able by means of the ground on its test contact 10", that ground being supplied over a circuit traceable from grounded spring 230 of relay 201 of the zone metering relay group, conductor 67, spring 44 and its break contact, conductor 59, spring 35 and its break contact, conductor 10 to the contact 10. For the pure assumed that. the zone markingswiteh ZM has associated itself with the repeater R, the manner in which their association is accomplishedbeing explained in detail hereinafter.

The equipment now being in readiness for the transmission of the second digit of the called number, the calling subscriber A dials that number, which in this case. is assumed to be the digit 5. The calling device of the calling telephone opens the previously described circuit for relay 22 ive times, that re lay falling back each time its circuit is opened, and. at spring 33 opens the previously described clrcuit for relay 23. Relay 23, being slow to release, because of the copper slug on its core,will remain energized during this impulsing. Spring 33, upon falling back, closes a circuit from ground through its break contact, conductor 61, through springs 40 and thence overtwo ,y paths in parallel, the one through the winding of relay 26 to battery, energizing that relay, the other over conductor 68 through the wiper 250 `of the zone marking switch ZM, conductor 68. springs 267, (relay 211 having been energized .when the zone marking switch associated itself with the repeater R), off normal' spring 266 at its break contact, through tlie-winding of relay 210, to magnet 213. Relay 210 and magnet 213 energize over this circuit. The relay, being slow to release, remains energized throughout the impulses, and the magnet 213 which is the vertical magnet of the zone marking switch ZM operates to elevate the wipers 278 and 279 onestep for each impulse, received. At the end .of the first impulse, the off normal spring 266, operates responsive to the vertical motion of the shaft, and transfers the circuit of the magnet 213 and the relay 10 so that it includes spring 266 and its make contact., spring 262 and its make Contact, and thence to the relay and magnet in series as before. The vertical magnet 213 of the zone marking switch ZM receives five impulses from the relay 22 of the repeater R, and operates to elevate the wipers 278 and 279 opposite the ifth level in its bank. At the end of the digit, the relay 210 receiving no more current, falls back and at armature 262 and its break Contact prepares the circuits of the switch ZM for the next digit. Returning now to the repeater R, the operationof slowto-release relay 26 responsive to the iirst impulse transmitted by relay 22, opens springs 44 without effect at this time, and at the spring 43 and its make contact closes a by-pass circuit for the relay`401 of the switch E2. Relay 401 is now held energized over a circuit from ground through its lower winding over trunk conductor 51 to the spring 32 and its make contact, through conductor 57,` spring 43 and its make contact, through resistance 39, through spring 34 and its make contact, conductor 50, through the upper winding of the relay 401 to grounded battery. Spring 32, which is included in this circuit, is under the control of relayv 22, and operates to open the above circuit each time the relay 22 deen function takes place, as explained in detail in the above reference', and the wipers come to rest on the cont-acts of the first idle trunk line -in that level, in this case assumed to be the trunk leading to the selector E3. When this idle trunk line is reached, the relay 403 of the selector E2 energizes, and at its upper and lower main springs and make contacts extends the trunk conductors 50 and 51 to the upper and lower windings of relay 404 and the selector E2, disconnecting the relay 401 from the. circuit in the well known manner. Returning to the repeater R,=wlien the rela;7 22 deenergized and at spring 32 opened a circuit of the relay 401, it also opened the circuit through the right hand winding of the impedance coil 31, conductor 56, through the upper winding ofthe polarized relay 24, that circuit having been previously traced. Relay 24, however, does not energize at this time for the reason that the lower or olarizing winding of this relay is not su ciently strong to operate the armature unaided.' the armature operating only when current iows through both the upper and lower windings inthe same direction, so that the magnetic fluxes produced thereby are assisting each' other. Relay 26, being slow acting because of the copper slug on its core, remains in an energized position throughout the transmission of the digit 5, falling back a brief interval after the relay 22 has come to rest energized at the completion of the transmission ofthe digit.4 The equipment is now in readiness for the transmission of the next digit of the called number.

The repeater R is now closing the circuit of the control relay of the selector E2, that selector being mechanicall and electrically the same as selectors E1 an E2, the operation of which is described in detail in the above reference. When the subscriber dials the third digit of the called number, in this case assumed to be the digit v6, line relay 22 operates six times at its springs 32 and opens the circuit of relay 404 of the selector E2, causing that selector to step its wipers vertically opposite the sixth level in this bank, whereupon the automatic rotary function takes place and the wipers stop on the `first idle trunk, as-v sumed to be the trunk line leading to the conf' nector H. In the repeater R, the operation of relay 22 closes the circuit for relay 26, as before, and transmits impulses over the conductor 68 which tlow through the wiper 250, the conductor 68', make contact and spring 267, through the spring 266 and its make contact, through spring 262 and its break contact, spring 259, winding of relay 208, through the magnet 212 to grounded battery. Relay 208 and magnet 212 energize in this circuit, the former remaining energized throughout the transmission of the impulses, and the latter following the impulses to advance the wipers 278 and 279 of the zone marking switch ZM in their second or rotary movement. On the completion of the transmission of the digit 6, the zone marking switch rotated wipers 278 and 279 into engagement withthe sixth bank contact in the lifth level, assumed to be the contacts 282 and 285, respectively. Upon the energization of the relay 208, a circuit is closed from ground through spring 254 through the upper winding of two-step rela 209, energizing that windin .which is of su cient strength to operate on y the spring 258. Spring 258 closes a circuit from ground through spring 265 and its make contact, relay 211 having been energized as above re- When the relay 208 `falls vback a short time after the last impulse inthe digit has been received, the short circuit is removed from the lower winding of relay 209, allowing current to flow through the two windings in series, to fully energize the relay and operate all ot the springs. A circuit may now be tracedl from ground through jumper 282', contact 282 now in engagement with wiper 278, through spring 256, wiper 253, through the winding of relay 207 to battery. Relay 207 energizes over this circuit and at springs 246 closes a locking circuit for itselt traceable from ground at spring 4l and its make contact, over conductor 63 through springs 246 f through the winding of relay 207 to battery.

Relay 209, upon energizing, at spring 259 opens the circuit for the relay 208 and the rotary magnet 212, thereby preventing their operation should the calling subscriber immediately dial another digit. Relay 209 also closes spring 260, completing the circuit from ground through springs 26() through the winding of magnet 214 to battery, energizing that magnet to advance the wipers 250-253 of the zone marking connecting switch to the next contact, thereby disconnecting the zone marking switch ZM from the repeater R. Relay 207, upon energizing, at springs 247 and 249 prepares a point in the metering circuit of the initial charge IC1 and the time charge TC, those circuits being held open elsewhere, pending the completion of the call.

The subscriber next dials the remaining digits of the call number, those digits in this case assumed to be 1 and 0, to'operate the connector switch H through its vertical and rotary motion, into engagement with the contacts. of the desired called line. The operation ot connector switch H, which is not an essential part of this invention, is well known to those skilled in the art, and need not be repeated indetail here, the switch being of the general type described on pages 53-62, inclusive, of the above mentioned text book. When the calling subscriber has completed the dialling of the digits of the-called number, the wipers of the connector are associated with the terminals leading to the called line, that line is seized and ringing current projected thereon in the' well known manner. When the called party answers this call, he removes the receiver from the telephone and closes a direct current circuit for the relay 407 of the connector H, energizing that relay. Relay 40'?, upf-xn energizing, reverses the battery connections of line relay 408, so that the lower groundedfwinding of relay 408 is connected to the upper trunk conductor 50 and Y the upper battery connected winding et relay 408 is connected to the lower trunk conductor 51. The current in the two windings of the polarized relay 24 of the repeater R is now flowing in the same direction, causing that relay to energize. Relay 24, upon energizing, at springs 38 closes the obvious circuit for relay 21 which energizes, and revverses the polarity of the calling line conductors 9 and 11 in an obvious manner. This reversal of the calling line is without particular ei'ect at this time. Relay 21, upon energizing,valso closes a circuit from ground through springs 29', conductor 55 through the normally closed contacts controlled by springs 231 of the zone metering relay group ZMR, through the winding of relay 202 to grounded battery, energizing the relay 202, which locks itself through spring 231 and its make Contact, conductor 63', to the grounded conductor 63. Relay 21, upon energizing, also operates springs 30 which open the circuit previously traced through the right hand winding of impedance 31 and closes a circuit through the right and leftI hand windings of this impedance in series, thereby increasing the impedance of `the bridge across the conductors 5() and 51 to the point where transmission is not materially reduced by the bridge. The calling and called subscribers may now proceed with the conversation, the zone meter relay group ZMR being in position to assess the proper charges against the calling subj scriber.

Associated with the zone metering relay group ZMR and the repeater R is the time metering switch TMS, which is individual to the one repeater. Connected to the banks of this switch are a plurality of cam operated springs, through the medium of which the time charges are assessed in accordance with the setting of the meter relay group ZMR. It is the Jfunction ot' the time metering switch TMS, to operate at the instant the called party answers and associate with'the zone metering relay group a set of springs which is just at the beginning of the time charge interval, under the control of time charge l, such as springs 324-326, inclusive, through the medium ot wiper 304 and the bankn the spring 325 has closed its make contact,

etc. Immediately before the cam 334 is in positionto operate its associated springs, it opens the circuit through wiper 304, by the half-height projection 333 of the cam engaging the main spring and opening the circuit closed through the back contact. The height of this portion of the cam is not sufficient to force the main spring against its` associated make contact. A short interval after the spring has broken away from its resting contact, the full-height portion 334 of the cam 335 engages the spring and closes the make contact, In .order to-`insure that the time interval for conversation allotted to the called ksubscriber is of the prescribed length, the time through springs 234, conductor 289, through springs 307, through the winding of mot-or magnet 301 of the time metering switch TMS to grounded battery. Magnet 301 energizes over this circuitand at springs 307 breaks its own circuit and deenergizes, advancing the wipers 303 to 306, inclusive, one step during the deenergization period. Viper 303 engages the next bank contact which is also assumed to be grounded and the wipers are advanced step by step until wiper 303 finds an ungrounded contact, which is assumed to be the contact associated with cam springs 325. The above traced circuit for magnet 301. now being held openby the cam spring 325, the Wipers come to rest and the time lmetering switch is in position to assess charges against the callingline. As the cam 335 progresses, full height cam 334 operates the spring 325 into engagement with its make contact. A circuit may then be traced from ground through spring 325 and its make contact through the next to the last bank contact now engaged by wiper 304, through spring 309 and its break contact, through the lower winding of relay 302 to grounded battery. The lower winding of relay 302 being magnetically weak, is only sufficiently strong to close springs 336 to apply the short circuitto the upper winding of the relay that is traceable from ground, spring 232 of relay 202, conductor 290, through spring 336 through the upper winding of relay 302 to the grounded mid-point of the relay. The cam projection 334 moves on, permitting the main spring 325 to return to its normal position, thereby removing thel short circuit from the upper winding of relay 302, which then operates fully and at spring 309 and its make contact prepares a point in yth'e time charge circuit. The operation of relay 202 responsive to the answering of the called party, also prepares a circuit for Athe initial' charge assessment which is made underlth'e control ofthe pick-up cam PU and the initial charge cams .1, 2, and 3. This Set of cams is common to the entire exchange and is rotating constantly at a medium rate of speed, that rate being somewhat faster than the time cams Cl-C, inclusive. lVhen the pickup cam PU gets into the proper position, it closes the springs 320 and a circuit may be traced from ground through springs 320, conductor 287, spring 233, spring 237 and its make Contact, to the mid-point of two-step relay 204 through the lower winding of the relay to grounded battery. The lower winding of relay 204 is sufficiently strong to operate only the springs 236 of the relay, those springs applying a short circuit to the upper winding of the relay, whichvmay be traced from ground, spring 232, to springs 236, through the upper winding of the relay 204 to the grounded mid-point of the relay. As the cam 310 progresses, the circuit is opened at spring 320, removing the short circuit from the upper winding of relay'204, permitting that relay to energize fully. Relay 204, upon energizing, at spring 238 prepares a point in the circuit of the meter charging relay 203. Since the call is extended to an exchange assumed to be in the first zone, relay 207 is energized and a circuit may be traced from ground through spring 323 and its make contact, when the cam 313 operates said spring, over conductor 293, through spring 244 and its break contact, through spring 247 and its make contact, through spring 241 and its break contact, through springs 238 through the winding of relay 203 to grounded battery. Relay 203 energizes over this circuit and at springs 235 removes direct ground from the conductor 62and substitutes in its place ground through the booster battery and resistance 222, through spring 235 and its make contact, conductor 62, spring 35 and its make contact, conductor 10, through contact 10 and its associated wiper, through the switch E through the wiper 4 of the switch C, through spring 7 and its make contact, through the Winding of the magnet of the meter M to grounded battery. The meter M is so adjusted that it will not operate when direct ground is placed on theconductor 62, but it will operate when booster battery is applied thereto, the meter M therefore operates once over the above traced circuit. and when the cam 313 passes out of range of the springs 323, relay 203 deenergizes and reapplies direct ground to the conductor 62, whereupon the magnet of the meter M restores to normal. The initial charge has been made against the calling subscriber and the equipment is in readiness to assess the time charges in accordance with the length of the conversation. When the pick-up cam PU again closes the spring 320, a circuit may be traced from ground through said springs over conductor 287, through springs 233, through spring 237 and its make contact, through springs 240, to the mid-point of relay 205 and thence through the lower winding to grounded battery. Relay 205, being a twoestep relay, operates only to close springs 239 When energized through the lower winding, that spring closing to short circuit the upper Winding and prevent the relay from pulling up completely. 7hen the pick-up cam PU moves out of range of the spring 320.V this short circuit is removed from the winding of relay 205 which energizes fully, operating the springs 240 to open the pick-up cam spring circuit just traced, and operating spring 241 to transfer the relay 203 from the control of the initial charge cam to the control of the time charge cam. Assuming now that the conversation is of suilicient length that the calling subscriber must be charged for an additional call, the cam controlling spring 325 again moves into mid-position when that spring engages the half-height portion of the cam333, this function being without effect at this particular time, other than to enter springs accessible to other switches, such as TMS. An instant later, the spring 325 comes into engagement with the portfon 334 of the cam 335, closing a circuit from spring 325 and its make contactA through Wiper 304, through spring 309 and its make Contact, over conductor 294, through springy 249 and its make contact, spring 245 and its break contact, through spring 241 and its make Contact, through springs 238, through the Winding of relay 203 to grounded battery. Relay 203 energizes over this circuit and at springs 235 ire-applies booster battery to the release trunk conductor 62 to operate the meter M to register another charge against the calling party A. This latter circuit for the relay 203 is periodically closed by the cam 335 as long as the conversation continues.

When the subscribers have completed the conversation and replace their receivers` relays 407 and 403 of the connector H restore, relay 408 opening the circuit of relay 409 which removes ground fronrthe release trunk conductor and restores the switches R2, E3, and H to their normal positions. Relay. 22 of the repeater R restores to normal, opening the circuit of release relay 23'A which restores and at spring 36 opens the circuit of relay 25, permitting that relay to remove ground from the holding conductor 63 to which relays 202 and 207 are locked. These relays restore, the former opening the locking circuit of relays 204 and 205, permitting them to restore to normal in readiness for the next call.

Returning now to the operation of the zone marking switch ZM at the above described time when relay 209 energized, a circuit through springs 264 of the magnet 214 was closedf which caused this magnet to energize and advance the wipers 250-253 inclusive, onto thenext set of bank contacts. 'lhe switch ZM, -having completed its functions in connection with the call then in progress, is ready to be associated with another repeater, such as R, to render that repeater capable of handling a call. Assume first that there are no other repeaters avail# able, a circuit will then be complete-d for the relay 216, leading from ground through the lower winding of thatrelay, through the resistance 221 to grounded battery. Relay 216 will energize and prevent the operation of the distributor at this moment. As soon as a repeater becomes idle, relay 25 therein falls back and at spring 41 and its break contact closes a circuit from ground over conductor 66, to short circuit the relay 216, 'permitting it to fall back andat armature 261 prepare a point in the circuit of the motor magnet 219 of theV distributor switch l). The function of the distributor switch D at this time is to associate itself with an idle zone marking switch ZM and to assist that switch in locating the idle repeater R, with which the switch ZM is to be associated in readiness for the present ground upon their respective bank contacts over which the wiper 274 rotates, that ground being supplied to spring 269 and its make contact, and the conductor 285. As soon as the. relay 216 falls back indicating that there is an idle zone marking switch, a circu-it may be traced from ground, spring 269 and its make contact, over conductor 285, wiper 274, througli relay 217 to grounded battery. Relay 217 energizes and at springs 263 opens the circuit of normally energized relay `218, permitting that relay to fall back after a brief interval. Relay 218, upon falling back, closes a circuit from the above ground on wiper 274, through springs 270, through spring 261 and its break contact, springs 273 through the winding of magnet 219v to grounded battery, causing that magnet to energize preparatory tor advancing the wipers 274-277 of the distributor switchmll to the next bank Contact. Magnet 219, upon energizing, at springs 273 breaks its own cir cuit and deenergizes, adrancihg the wipers 274-277, inclusive, on the the next contact. lf that zone marking switch is engaged, wiper 274 will again encounter ground and a circuit forl magnet 219 will again be completed as before. As soon as an idle zone metering switch is encountered, the circuit for magnet 219 and the circuit for relay 217 are no longer closed, the latter falling backV to complete the circuit for `relay 218. Assuming now that when the magnet 214 of the zone marking connecting switch advanced the wipers 250-255 to thair next bank contaet,.that bank contact was busy, i. e., the repeater, such as R, associated with that contact placed ground on the conductor 65 through the medium of spring 42 and its make contact. A circuit may now be traced from that ground to wiper 251 of the zone marking connecting switch through conductor 65', springg264 and its break contact, conductor 282 through wiper 277 of the distributor switch D, spring 271 and its make contact, wiper 275, conductor 284, through springs 257 of they magnet 214, and through the winding of the magnet to battery. Magnet 214 energizes over this circuit preparatory to advancing the wipers 250-253 on to the next bank contact. The energization of relay 218 closed another circuit traceable from ground through spring 272, wiper 276,

. conductor 283, through the upper terminal of the relay 211, that relay' now being short circuited by havingl ground potential at both of its terminals, it is prevented from energizing. Magnet 214, upon energizing, interrupts its own circuit at 257, falls back to advance the wipers 250-253 one step. As long as the wiper 251 engages grounded contacts, the

above circuit will be completed for the magnet 214, which will operate with a buzzerlike action to rotate the switch wipers. As soon as Wiper 251 fails to find ground, magnet 214 comes to rest deenergized and relay 211 ener izes over a circuit traceable from ground-t rough springs 272, wiper 276, conductor 283, through the winding of relay 211, through springs 257 through the winding of magnet 214 to grounded negative battery. Magnet 214 is prevented from energizing'in this circuit by the resistance ofthe relay 211.

' Relay 211, upon energizing, closes a circuit at springs 264 from the grounded terminal of the relay, through conductor Wiper 251 now assumedv to be in engagement with the contactleading to the conductor 65, through springs 42 of the repeater R, conductor 64 through the winding of relay 201 of the zone metering relay group ZMR, to grounded battery. Relayv201 energizes over this circuit and at spring 230 and its make contact closes' Vla circuit from ground through sprin cuit over conductor 285, wiper 274, relay 217 to grounded battery, energizing relay 217 which at springs 263 opens the circuit for relay 218.y Relay 218 falls back after an interval, and at spring 270 closes a point in the motor magnet circuit of the distributor switch D. If there is another idle zone marking switch ZM and an idle repeater R, the distributor switch rotates its wipers into engagement with that zone marking switch, which will seek out the idle repeater in the above described manner. When the relay 211 of the zone marking switch energized, at springs 265, it removed ground from the conductor 286, thereby permitting relay 216 to energize in the event that the zone marking switch ZM happens tobe the only one idle at the moment.

In the foregoing example, the operation of the system was described in connection with a call to the first zone, for which the initial charge was one unit, and the time charge one unit per time interval. If for example, calls were to be directed to the second zone, the switch E4, being assumed to be the incoming selector in an ofi-ice in the second zone with respect to the oice of the calling subscriber A, the first and second digits transmitted through the` repeater R to position the switches E2 and E* to direct the call to the third office, also position the zone marking switch ZM in the manner previously described so that the Wipers 278 and 279 would come to rest on contacts, such as 284, and 281. The particular digit necessary to route the call to the second zone, or to any zone for that matter, are inconsequential, for the bank contacts over which the wipers 278 and 279 may be jumpered at will through the jumpers in the distributing frame F, are left open. Contacts281 and 284 with which the wipers 'are assumed to be associated following the setting of a call to the second zone are jumpered so that ground appears on contact 284 while 281 is left open. .A circuit may then f be traced from ground through the jumper 284', contact 284, wiper 279, springs 255, wiper 252, through the Winding of relay 206 to battery, energizing the relay 206 which locks itself to the grounded conductor 63fat spring 242. lVhen the called party has answered and the pick-up cam PU has operated the springs 320, the circuit is closed for the relay 204, partially operating' it. When springs 320 are opened the relay pulls all the Way up closing a point in the operating circuit of relay 203 which circuit is completed from initial cam IC2, spring 322, conductor 291, through springs 243, spring 247 and its break contact, spring 241 and its break contact, springs 238 through the relay 203, energizing that relay to apply the initial charge to thecalling line. Cam IC2 contains two projections which operate the springs 322 twice for each revolution of the cam, so that the relay 203 will be energized twice to apply two impulses of booster battery to the release trunk before the pick-up cam 310 operates the springs 320 to energize the relay 205 to 'throw the relay 203 under the control of the timing cam. As before, upon the response of the called party, the timing switch TMS operates, picking out a set of timing cams under the control of wipers 303, and, because of the setting of the relays 206 and 207, the springs controlled by the second time cam TC2 are used, the circuits being completed through the wiperl 305. It will be noted that the timecam C2 contains two full height portions so that the springs, such as spring 327, for example, close a circuit over vwiper 305 twlce for each revolution of the cam. In this manner, the initial charge of two units 'is repeated at the end of each time interval.

If the call originating in the station A has selected an ollice in the third zone, the zone marking switch ZM will be positioned by the second and third digits of the call number so that the wipers 278 and 279 will be in engagementwith contacts, such as 280 and 283, both of which are jumpered to ground. When the relay 209 energizes, both relays 206 and 207 will be energized, the former over a circuit including wiper 252, springs 255, and Wiper 279 and the contact 283, and the latter over a circuit including wiper 253, springs 256, wiper 278 and contact 280. When the called party has answered and the pick-up cam has operated as before explained, a circuit will be completed by the initial charge cam 103, from 'ground through springs 321, conductor 292, through spring 244 and its make contact, spring 247 and its make contact, spring 241 and its break contact, and thence over the previously described circuit through 203, energizing that relay three times to apply three impulses of booster battery to the release trunk, as before explained. When the pick-up cam energizes, relay 205, then transfers control of relay 203 from the initial charge cam set to the time charge cam set, the circuit will be completed from a time charge cam spring, such as 330, through the wiper w306, conductor 296, through spring 248 and its make contact, spring 245 and its make contact, spring 241 and its make contact, and thence to relay 203. It will be noted that the cam C3 contains three full height projections which operate the springs, such as 330, three times for each revolution of the cam shaft.

While I have chosen to show my invention in connection with a particular form of apparatus, I have done so merely by way of example, as there are many modiiications which willbe app'arent to one skilled, which may be made Without departing from the scope of the invention.

Having thus described my invention, what I consider new anddesire to have protected by Letters Patent is pointed out in the appended claims.

What is claimed is:

l. In a telephone system, a calling line, a message register associated with said line, a plurality or' automaticswitches accessible to said line and used in setting up connections to called parties in a plurality of distant exchanges, zone metering equipment associated with certain of said automatic switches, a zone marking switch arranged to be temporarily associated with said zone metering equipment, means on said calling Vline for transmitting impulses to said automatic changes, trunk lines between said exchanges,

a repeater in the near end of said trunk line, an automatic swltch in the far end of said trunk line, callmg lines inthe near end exchanges, automatic switches through which said calling line has access to said repeater, zone metering equipment associated with said repeater, a zone marking switch transiently associated with said 'zone metering equipment, a time metering switch associated with said zone metering equipment and having ac cess to a plurality of time metering cam springs, means in said calling substation for transmitting impulses to operate said repeater to set said automatic switch in position to extend the call to a distant called subscriber,

.means responsive to said impulses for operating said zone marking switch to determine a charge to be assessed against said calling line, means yresponsive to the setting of said zone marking switch for registering said charge in said zone metering equipment, means operated by the response of the called party for causing said time metering switch to associate itself with a certain set of said time operated springs, means for thereafter causing said zone metering equipment to assess said predetermined charge against said calling subscriber, and means operable through said time metering switch for repeating said charge at definite intervals throughout the conversation.

3. In a telephone system, a plurality of exchanges, trunk lines between said exchanges, a repeater for each trunk, zone metering equipment and a time metering switch permaa plurality of zone marking switches having access to said zone metering equipment, a distributor' switch having access to zone marking switches, means for rendering said repeaters unselectable until a zone marking switch is associated therewith, means for causing said distributor switch to associate itself with an idle one of said zone marking switches and to associate that zone marking switch with an idle one of said repeaters, and means responsive to the completion of said association for rendering said repeater selectable, and for disassociating said distributor switch from said zone marking switch.

4. In a telephone system, a plurality' of exchanges, trunk lines between said ex-- changes, a repeater for each trunk, zone metering equipment and a time metering switch Y permanently associated .with each of said re- ;eaters, a p rality of zone marking switches iaving access to said zone metering equipment, a distributor switch having access to vso zone marking switches, means for rendering said repeaters unselectable until a zone mark- '.ng switch is associated therewith, means for causing said distributor switch to associate itself with an idle one of said zone marking switches and to associate that zone marking switch with anidle one of said repeaters, means responsive to th completion of said 4association for renderin said repeater selectable, and for disassoci ting said distributor switch from said zone markin switch, and means for preventing he furt er operation of said distributor swi ch unless it has access to'another idle zone arking switch which has access to another idle repeater.

5. In an automatic elephone s stem, a plurality of exchanges, runk lines etween said exchanges, repeaters in said trunk lines, zone metering equipment associated with said re-l eaters a zone mar n switch and a distributor switch 7transiently associated with said zone metering equipment, wipers on said zone marking switch, a plurality of rows of contacts with a plurality of contacts in each row accessible through the wipers of said zone marking switch, a calling line and means thereat for transmitting impulses vto said reeater to set up a connection to a distant called ine, means operated by` said impulses for setting said zone marking switch wipers into `engagement with certain ones of said bank contacts, said zone metering equipment controlled through said wlpers to assess a certain charge against said calling line, and means' associated with said wipers for at will changing said charge.

' 6. In a telephone s stem, a plurality/of exchanges, trunk lines etween said exchanges, repeaters in said trunk lines, zone metering equipment individual to and permanently asi sociated with each of said repeaters, a zone marking switch common to said repeaters and 'transiently associated with said repeaterl in- -ing said repeater to set a call and means for simultaneously operating said marking switch to register a charge in said zone metering equipment.

7. In a telephone s stern, a plurality of exchanges, trunk lines between said exchanges, repeaters in said trunk lines, metering relays and a time metering switch individual to and permanently associated with each of said repeaters, a plurality of cam operated time charge springs accessible through the banks of said metering switch, a calling line, means controlled therefrom for operating said repeater to extend a connection to a called line, means operative upon the response of the called party for causin said metering switch to select certain ones o said cam springs and means jointly controlled by said selected springs and metering equipment for assessing rn elapsed time charge against said calling 8. In a telephone system, a plurality of exchanges, trunk lines between said cxchanges, repeaters in said trunk lines, metering relays and a time metering switch individual to and permanentl associated with each of said repeaters, a pl'urality of timing spring sets common to said repeaters and accessible through the banks of said switch,

cams for operating said springs, a half-height portion on certain of said cams, a test wiper on said time metering switch, circuit means completed through said wiper for stepping said switch into engagement with a set of cam springs made selectable by said half height portion to mark the beginning of a time interval, and cam controlled .means for thereafter periodically assessing a time charge through said meter relays.

9. In a telephone system, a group of interoice trunks each containing a repeater, zone and elapsed time, metering equipment comprising a group of constantl moving zone cams and a group of constant y moving timing cams common to said trunk group, a group of meter relays and a time meterlng switch individual to each trunk of the group, a plurality of zone marking switches and a distributor switch common to said trunk group, means controlled jointly by said marking switch and distributor switch for associating said marking switch with an idle one of said repeaters, means for then rendering said repeater selectable, means for operating said repeater to extend a connection and for simultaneously operatin said associated marking switch to determine a charge, means in said meter relays for associating one of said zone cams with said repeater and for causing said time switch to associate a certain set of said time cams with said repeater, and

-means controlled lirst by said zonevcams and after such registration takes place, and means for subsequently assessing said registered charge on said message register.

l-l. In a telephone system, a trunk, a calling line having access to said trunk, a message register on said line, zone metering equipment permanently associated with said trunk, a marking switch temporarily associated therewith, means on said calling line :tor extending a connection over said trunk said marking switch operating simultaneously to determine a charge therefor, a group of relays for registering said charge in said zone meterin equipment, means for disassociating said marking switch from said trunk as soon as registration has taken place, and means for releasing said trunk and zone metering equipment without assessing said registered charge if said extended connection is incomplete.

12. In a telephone system, a trunk, a calling line having access to said trunk, zone metering equipment permanently associated with said trunk, a distributor switch, a plurality of marking switches, means for associating said distributor with an idle one of said marking switches, means for associating said idle marking switch with said trunk, and tor disassociating the distributor therefrom, means on said line for extendin a call over said trunk and for simultaneous y operating said marking switch to determine a charge to be assessed against the calling line, and

- means for registering said charge in said zone till metering equipment and for disassoeiating paid marking switch therefrom..

13. In a telephone system in which there are a number ot exchanges, means including one ot a plurality of trunk lines for extend' ing a connection between two of said exs changes, register equipment individual to each respective trunk, and means common to said trunk lines and associated with the trunk line seized before its seizure to render it seizf able and responsive after the seizure of the trunk to cause said register equipment to function and set up a circuit condition pe-A register switch and a meter operating switch individual to said repeater, means in said register switch normally guarding the trunk against seizure by a calling subscriber attempting to set up a call, a zone marking switch, means for causing said last switch to seize said trunk only when the mentioned guarding potential is present, and means in said register switch responsive to its seizure for conditioning said trunk for seizure by a calling subscriber. y

15. In a telephone system, acalling line, a meter individual to said line,trunk lines, means including automatic switches operable over one or more of said trunk lines for eX- tending a connection to a called line, lapse time meter control equipment individual to one of said trunk lines, and means common to said trunk lines for setting the individual meter control equipment of a trunk used in a condition to control the calling lines meter in a characteristic manner following the response of the called party and for then immediately ldisassociating itself from said trunk.

16. In a telephone system, a calling line, a meter for said line, trunk lines, automatic switches controlled over one of said trunk lines to establish a -connection with a called line, a group of meter control relays individual to the trunk used, a pair of conductors having associated means for causing operations of the said meter, a pick-up conductor common to said trunks and means associated therewith for closing an operating circuit for one of said meter control relays to render one of said conductors effective, and a second relay ot the group thereafter responsive to the means associated with said pick up conductor to transfer the meter control to the other conductor.

17. In a telephone system, a calling line equipped with a meter, means including a plurality of automatic switches and one of a plurality of trunk lines for setting up a connection to a called line, a repeater individual tothe trunk line used, a zone metering register relay group also individual to said trunk, zone marking switches common to said trunks but always associated with one or another of said trunks, and means in said relay group for preventing the seizure of the trunk to which it is individual unless one `ot said zone marking switches is associated with it.

18. In a telephone system in which zone metering equi ment is provided for assessing charges or connections in accordance with the zones connected with and in accordance with the duration of a call, a trunk line having individual thereto a zone metering register relay group, an automatic switch also associated with said trunk effective to cause the call to be char ed for in 4a manner and at a rate determine by the condition of said relay group, and another switch associated with the seized trunk only for the period required to properly condition said zone metering relay group.

19. In a telephonesystem, a trunk, a calling line having access to said trunk, a message register on said line, zone metering equipment associated with said trunk, a marking switch also associated therewith, .neans on said calling line ffor extending a connection over said trunk said marking switch operating simultaneously to determine a charge therefor, a group of relays for registering said charge in said zone metering equipment, means for disassociating said marking switch from said trunk, and means for releasing said trunk and zone metering equipment Without assessing said registered charge if said extended connection is in- .omplete.

20. In a telephone system in which zone metering equipment is provided for assessing charges for connections in accordance with the zones connected with and in accordance with the duration of a call, a trunk line having a zone metering register relay group associated therewith, means also associated with said trunk effective to cause the call'to be charged for in a manner and at a rate deermined by the condition of said relay group, and other means associated with the seized trunk only for the period required to properly condition said zone metering relay Group.

Inxwitness whereof, I hereunto subscribe my name this 10thvday of February, A. D.,

' RUDOLPH F. STEHLIK.` 

